Scientists finally uncover the weight of Milky Way

The Whirlpool Galaxy (M51a) and companion galaxy (M51b). This Hubble Space Telescope image represents a merger between two galaxies similar in mass to the Milky Way and the Large Magellanic Cloud.NASA, ESA, S. Beckwith STScI), and The Hubble Heritage Team (STScI/AURA

A team of International scientists from NASA and the European Space Agency (ESA) has finally determined the weight of the Milky Way by using the Hubble and Gaia telescopes. After the research, scientists revealed that the Milky Way weighs the same as 1.5 trillion suns and measures 256,000 light years across.

Researchers made this conclusion after combining data from 46 globular clusters, that comprises of thousands of stars that swarm around the centre of the Milky Way.

"We were lucky to have such a great combination of data. By combining Gaia's measurements of 34 globular clusters with measurements of 12 more distant clusters from Hubble, we could pin down the Milky Way's mass in a way that would be impossible without these two space telescopes," said Roeland van der Marel of the Space Telescope Science Institute in the US, Eurekalert.org reports.

Researchers also revealed that the Milky Way can be considered as an above average galaxy in terms of its size. Earlier, it was speculated that the mass of the Milky Way ranged from 500 billion to 3 trillion times the mass of the Sun. Scientists have been always uncertain about the exact mass of the galaxy as they often found it difficult to measure the distribution of dark matter, which makes up about 90 percent of the universe.

"We just can't detect dark matter directly. That's what leads to the present uncertainty in the Milky Way's mass -- you can't measure accurately what you can't see," said Laura Watkins, a researcher at the European Southern Observatory in Germany and the lead author of the study.

To solve the problem of associated with dark matter while analyzing the weight of the Milky Way, the team relied on measuring the velocities of globular clusters. Scientists also added that when the galaxy is more massive, the clusters will move faster under the pull of its gravity.